Question:
Our professor told the TA that he needed his help.

he
Answer:
Our professor
Question:
Johnson wanted to make friendship with David, because he is well connected.

he
Answer:
David
Question:
Brock understood the material better than Tracy because he was paying attention.

he
Answer:
Brock
Question:
The starships transported the colonists to their new planet since they will be creating a new settlement.

they
Answer:

the colonists